EGR Valve Control Circuit – Voltage Below Normal or Shorted to Low Source
|Fault Code: 2351
EGR Valve Control Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at the EGR valve motor circuit.
Possible low power. Power removed from EGR valve motor.
EGR Valve Control Circuit
The electronic control module (ECM) controls the EGR valve, opening and closing it based on various operating conditions. The EGR valve is opened and closed by a DC motor that receives voltage from the ECM on the EGR valve motor signal (+) and (-) circuits. To open the valve, the motor receives voltage on the EGR valve motor signal (+) circuit. To close the valve, the motor receives voltage on the EGR valve motor signal (-) circuit.
The EGR valve motor is located on the exhaust side of the engine and is attached to the EGR valve assembly, which is mounted to the exhaust manifold. Refer to Procedure 100-002 for a detailed component location view.
The ECM monitors the voltage level of the circuit and logs a fault code if the voltage level indicates a short to ground. This fault is always set inactive when the keyswitch is turned ON. If there is a failure of this circuit, the fault code will not be set active until the valve has been actuated. For these reasons, this troubleshooting tree must be used of both active and inactive fault codes. This also means that the only sufficient way for making sure that the repair is effective is to run the INSITE™ EGR Valve Test. Running the engine may not be enough to verify that the fix was effective.
A possible cause of this fault is EGR valve motor output (+ or -) leads shorted to ground in the harness, EGR valve motor, or ECM.